Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavioral facts beyond those: it only applies 'while a video is being made' and it is free ('Cost: Free: no credits'), which is exactly the kind of cost/auth context annotations cannot express. It stops short of describing polling cadence or what happens after completion.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences, front-loaded with the triggering condition and core action before the field list, usage advice, and cost note. Every sentence earns its place, though 'Cost: Free: no credits' has redundant phrasing that could be tightened.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present the description need not explain return values — yet it still previews them usefully — and annotations carry the safety profile. Between the timing constraint ('while a video is being made'), the narration guidance, and the cost note, an agent has everything needed to call this correctly during a render.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

There is a single parameter (video_id) and schema description coverage is 100%, so the schema already documents it fully as 'The video id from list_videos.' The description mentions no parameters at all, so the baseline of 3 applies — the schema does all the parameter work.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('read what the editor is doing') and enumerates the returned fields (stage, minutes left, paper edit, steps, names heard), which is far more concrete than a tautology. It does not, however, explicitly distinguish itself from closely related siblings such as check_video or list_videos, so it lands at clear-but-undifferentiated rather than a full 5.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a clear when-to-use rule: 'Use it to narrate progress instead of waiting silently,' which frames it as a polling/narration tool during an in-flight render. It supplies no exclusions or named alternatives (e.g., what to call once the video is finished, or how it differs from check_video), so it is strong context without the full when-not guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.